Grounding Schemes for Small Satellite Systems

Author(s):  
P. Srinivas ◽  
Kumar Rahasyam ◽  
N. Beebamma ◽  
PSR Srinivasa Sastry
2021 ◽  
Author(s):  
Sarah Hardacre

The desire to bring space travel to a wider range of missions and uses has driven the market to using smaller and thus more affordable satellite systems. The Canadian Space Agency is completing the design and construction of a small satellite named QuickSat, which will utilize a magnetometer as one of its attitude and orbit determination instruments. A test bed comprised of three pairs of Helmholtz coils was used for hardware in the loop testing of the magnetometer. Testing was initially completed to prove the capabilities of the test bed, and then was completed to demonstrate the capabilities of the flight qualified magnetometer. The three pairs of Helmholtz coils were driven by data calculated from a spherical harmonic model of the Earth's magnetic field The coils were controlled using a robust controller and the magnetometer was used to drive the B-dot control law in the QuickSat simulation. The Ryerson Attitude and Control Experiment (RACE), which is a small satellite sized platform, free to spin about one axis on a near frictionless air bearing, was utilized to develop and test a system to deal with redundancy of satellite sensors. The possibility of missing, noisy or erroneous output during flight requires that a filter be applied to a satellite's flight code to determine with accuracy the attitude and orbit of the spacecraft. It was thus decided that a Kalman Filter be applied to RACE. The Kalman filter was applied to the RACE simulation successfully and initial hardware testing was carried out.


2020 ◽  
Vol 143 (1) ◽  
Author(s):  
Steven A. Isaacs ◽  
Caelan Lapointe ◽  
Peter E. Hamlington

Abstract With easier access to space and the growing integration of power-dense components, small-scale thermal management solutions are increasingly in demand for small satellite systems. Due to the strict mass and volume requirements commanded by such power-dense small spacecraft, heat pipes with thin and flat architectures provide nearly ideal solutions for the efficient transfer and dissipation of heat. Unlike traditional heat pipes, however, the performance of thin heat pipes is heavily dependent on details of the internal heat pipe structure, including the vapor core geometry and structural mechanical characteristics. In this study, the development and testing of a new computational modeling and optimization tool are presented for the design of thin flat heat pipes. The computational model is described in detail and includes parameters that define properties of the liquid wick, vapor core, and structural case. The model is coupled to a gradient-based optimization procedure that minimizes a multi-objective cost function for a range of operating conditions. The cost function is expressed as the weighted sum of the total temperature drop, the liquid/vapor pressure ratio, the total mass of the heat pipe, and the structural deflection of the heat pipe during operation. The combined computational modeling and optimization tool is then used to design a copper-methanol flat heat pipe for a small satellite mission, where the optimization is performed with respect to both cold and hot orbital conditions. Validation of the optimized heat pipe is performed using computational fluid dynamics (CFD) simulations of the initial and final designs.


2015 ◽  
Vol 114 ◽  
pp. 65-78 ◽  
Author(s):  
N.H. Crisp ◽  
K. Smith ◽  
P. Hollingsworth

2019 ◽  
Vol 10 (4) ◽  
pp. 331-340 ◽  
Author(s):  
A. A. Spiridonov ◽  
D. V. Ushakov ◽  
V. A. Saechnikov

Currently, ultra-small satellite aresubjectstostringentrequirementsintermsoftheaccuracyof determining the position of the satellite in orbit, while the satellite is the subject to restrictions on mass, size and power consumption. The aim of this work is to simulate of navigation receiver operation for the ultra-small satellite with restrictions on energy consumption and computational resources.The operating conditions are considered and the requirements to the onboard navigation receiver for the ultra-small satellite are determined. The navigation receiver operation at the initial stage, performance testing, error detection, analysis of the reliability of the solution of the navigation-time determination problem are described.The structure of the design ballistics problems for orbit prediction of ultra-small spacecraft and navigation satellites, radio visibility intervals for GLONASS and GPS systems, parameters of navigation signals have been developed.The motion relative to the satellite systems GPS and GLONASS for a preliminary orbit of СubeBel-1 have been simulated. The Doppler dynamics of the GPS satellite signals in the receiver without restrictions on the relative speed for one day has been calculated. Radio visibility intervals for GPS and GLONASS satellites were calculated and optimal conditions for the cold start of the navigation receiver with a relative speed limit (Vr < 500 m/s) for 1 hour of operation both in separate and in joint operation on both systems were determined.To test the verification methods of the experimental data of the СubeBel-1 satellite, the operation of the navigation receiver of the Nsight satellite was studied according to the received telemetry from the beginning of its flight until the moment it entered stable operation.It is shown that the telemetry data of the navigation receiver at the testing stage had a significant error. After software correction, the navigation receiver worked steadily throughout the week of observation, the error of longitude and latitude measurements did not exceed 0.2 degrees.


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